Method for clarifying liquids and producing useful products



Patented Dec. 31, 1935 METHOD Fon CLARIFYING LIQUIDS AND PRODUCINGUSEFUL PRODUCTS John C. Bird, Elizabeth, N. J.,- assignor to StandardOil Development Company, a corporation of Delaware No Drawing.Application December 21, 1931, Serial No. 582,508

18 Claims. (01. 210-9) This invention relates to a method ofdecolorizing liquids of dissolved or suspended coloring matter and tothe production of useful products.

When hydrocarbon oils such as petroleum oils,

coal tar distillates, products of liquefaction of coal, lignite, peat,etc. and'their distillation or conversion products of destructivedistillation, hydrogenation, destructive hydrogenation and the like aretreated with strong sulfuric acid or sul- 10 furic anhydride, aby-product commonly known as acid sludge is formed. This product isnormally heavier than the oil treated and separates as a bottom layer,especially when the treating is conducted with fuming sulfuric acidcontaining about by weight free sulfuric anhydride.

This sludge is usually considered to consist of sulfonic acids, excesssulfuric acid, and other organganic material, some of-whichare insolution while others are colloidally dispersed throughout 20 thesludge. This invention embodies using such acid sludges, or sulfonicacids derivable therefrom, for the decolorization and clarification ofaqueous liquids and the production of new and valuable pigments orlakes..

My invention will be fully understood from the following-example:

An acid sludge, such as that obtained by treating white oil stock withstrong sulfuric acid, is mixed with water in such proportion to giveafter settling an aqueous bottom layer containing approximately to 45%sulfuric acid. The mixture is then heated to approximately 80 to 100 C.and is agitated continuously with a stream of ,steam or air to removesulfur dioxide. After 35 most of'the sulfur dioxide is drawn off thematerial is allowed to stand and settle. The bottom aqueous sulfuricacid layer is then drawn off and may be purified and concentrated forreuse, according to known methods.

40 The remaining top layer is called. a washed acid sludge, and-containssubstantially all .the organic material of the original sludge with asmall amount of free sulfuric acid, depending upon the extent of thewater dilution. On addition of water soluble compounds of calcium orbarium to this acid sludge, a precipitate is formed which appears toconsist largely of'sulfonates.

The washed acid sludge is diluted with about 1 to 5 volumes of water andis added to an aqueous solution of a water soluble dye. A solution ofbarium hydroxide is then added in suflicient quantity to neutralize theacid present. A bright coloredprecipitate is formed which containssubstantially all the dye, leaving a clear and substantially colorlesswater solution. This precipitate retains the coloring mattertenaclously, so that it can not be removed by ordinary means,

as by washing with water. The precipitate may be readily suspended inwater, and may be used ininks, pigment wall colors, and for coloring 5paper or other fibrous or textile materials. This precipitate is also avaluable pigment and may be used in surface coating compositions, suchas paint, for impregnation in plastic moulded or compounded articles,and for other uses for 10 which pigments and lakes are generallysuitable. In explanation, it appears that the heavy sulfonic acid saltsadsorb and retain the dye. Some barium sulfate is also precipitated dueto the free sulfuric acid remaining in the sludge, 15 and is valuable asa filler. If additional filler is desireda larger proportion of freeacid may be left in the sludge, or additional acid may be added. Theprecipitate also adsorbs some light acid salts which act as penetratingor wet- 0 ting agents.

Bases, for example, oxides or hydroxides of other alkaline earth metals,such as calcium or strontium may be used in place of barium compounds inthe clarification step, and in gen- 25 eral metals capable of formingwater-insoluble sulfonates are suitable for clarification-ofthe liquid.Barium salts are especially preferred when the precipitate is to be usedas a pigment or lake, .while the calcium and strontium pre- 30 cipitatesare not as pure in color, and are more sticky and difilcult to handle.Lime or other calcium compounds are suitable, however, for crudeindustrial clarifications, as for the treatment of textile mill wastewater, muddy water, ,35

sewage, and similar liquors.

The crude acid sludge may be used directly, without was: me, if desired,and is especially suitable where the solutions to be clarified arealkaline. 40

The washed sludge may also be subjected to additional purificationbefore use, if desired, and the free sulfuric acid and the sulfonicacids capable of forming water-soluble alkaline earth sulfonates andother organic matter may be 45 removed by various methods. Extraction ofthe sludge with water insoluble organic solvents such as secondary butylalcohol, tertiaryamyl alcohol and the like, separates free sulfuricacid. Extraction with water soluble organic solvents such 50 as methyl,ethyl or isopropyl alcohol, acetone, and the like, separates tarrymatter and oil, and, if the sludge has been previously neutralized withan alkali, alkali sulfates.

The original or washed sludge may also be 55 filtrate may then beevaporated to the corresponding material neutralized with an alkalimetal compound or ammonia and then used directly for the clarification0. liquids as already described. The purified water soluble sulfonicacids, capable of forming water insoluble alkaline earth sulfonates, and.their water soluble salts, such as the sodium sulfonates, may also beused.

' sugar syrup may be substantially clarified with any of the sludgesdescribed, these highly purified sulfonic extracts are preferred.

The filtrate remaining after the formation of a precipitate from thewashed acid sludge,' as above described, containswater soluble alkalineearth sulfonates. These may be converted into alkali salts by. theaddition of sodium carbonate, potassium sulfate, 'etc. the resultinginsoluble barium salt being removed as a precipitate. The dryness bymeans of a drum or spray drier. The alkali sulfonates so produced arepowerful wetting agents or detergents, do not stain fabrics, paper orother absorptive materials with which they are impregnated, and differin t respect from obtained from calcium or magnesium salts which hasbeen found to cause a dark brown stain. Furthermore the alkali compoundsprepared in this manner will not form a precipitate with hard or saltywater.

In clarifying colored aqueous solutionscontaining suspended, material bythe forming of a precipitate therein from acid sludge with calcium orother metals than barium, the liquid after the precipitation thoughclear may remain somewhat colored. In this case it may be desirable touse additional means to eflect the complete'decolorization of thesolution. This may be done by treating the aqueous solution with smallamounts of substances possessing high.

coagulating power. For example, an addition of about 1%-of aluminumsulfate or chloride may improve the color to a great extent.

This invention is not to be limited to any theory of the chemicalconstitutionof the acid sludges described herein or their derivatives,nor by examples given for purpose-of illustration, but only by thefollowingclaims in which I wish to claim all novelty as far as the priorart permits.

1 claim: 7 1. An improved method for removing coloring matter fromaqueous liquids comprising adding water soluble compounds selected fromthe group consisting of sulfonic acids and their salts capable offorming substantially w'ater insoluble alkaline earth sulfonates to saidaqueous liquid, causing the formation .of water insoluble sulfonatestherein as a precipitate whereby said coloring matter is adsorbed onsuch precipitate and removing said precipitate from said liquid.

2. An improved method for removing coloring matter. fromaqueous liquidscomprising adding thereto a water soluble sodium sulfonate capable offorming water insoluble alkaline earth sulfonate and an alkaline earthcompound to form a precipitate in said liquid comprising awaterinsoluble alkaline earth sulfonate containing said coloring matter, andremoving said precipitate.

3. Process according to claim 2 in which an aqueous solutioncf sodiumsulfonate prepared from a 'petroleumoil acid sludge and capable ofproducing water insoluble alkaline earth sulously clarifying aqueousprecipitating the '15. As a composition of matter, a Pigment 6o.

ing of dissolved coloring .matter and fonates is added to the aqueousliquid and an 'aqueous solution of an alkaline earth compound is addedto cause the formation of precipitate.

4. An' improved process for decolorizingan aqueous solution of a dyecomprising adding 5 thereto a washed hydrocarbon oil acid sludgeconsisting substantially of sulfonic compounds, separately adding anaqueous solution" of an alkaline earth compound and removing aprecipitate of alkaline earth sulfonates containing said 10 dye.

5. Process according to claim 4 in which a sub-= stantially colorlessaqueous solution of a petro-. leumoil acid sludge is added to supply thewater soluble sulfonates.

6. Process according to claim :4 in which an aqueous solutionof bariumhydroxide is added to the aqueous solution of dye and acid sludge toneutralize the acidic constituents of the acid. sludge and to form aprecipitate comprising ba- 20 rium sulfonate.

7'. Process according to claim 4 in which the alkaline earth compound isadded as an aqueous suspension of an alkaline earth oxide.

insoluble substance obtained by reaction of a 30 hydrocarbon oil acidsludge consisting substantially of sulfonic, compounds with an alkaline'earth and containing adsorbed coloring matter.

10. A composition of matter comprising a water insoluble alkaline earthsulfonate contain- 35 ing adsorbed coloring matter.

11. A composition of matter comprising a water insoluble alkaline earthsulfonate containing adsorbed coloring matter and prepared from thesulfonic acids of hydrocarbon oil acid sludge. 40

'12-. A composition of matter comprising a water insoluble precipitateformed from a hydrocarbon oil acid sludge consisting substantially ofsulfonic compounds anda reactive compound of barium in an aqueousliquid-containing adsorbed 45 dye.

13. The process which comprises simultaneliquids containing substancesof the class of coloring matter and producing a useful pigment 50 byprecipitating with a petroleum sulfonic compound an insoluble sulfonatesalt in said liquids, whereby the coloring matter is adsorbed bytheprecipitate.

14. Process according to claim 13, in which the 55 precipitation iseffected by first adding to the colored liquid a water-soluble petroleumsulfonate and then adding a compound capable of sulfonate as aninsoluble salt.v

comprising an insoluble petroleum sulfonate salt containing adsorbedcoloring matter. 16. An improved method of clarifying aqueous liquidscontaining substances of the class consistsuspended c5 solids,comprising adding thereto a hydrocarbon oil acid sludge consistingsubstantially of sulfonic compounds, forming a precipitate of a waterinsoluble sulfonate in said liquid, and removing said precipitate. 7 17.An improved process for clarifying aqueous liquids containing substancesof the class consisting of dissolved coloring matter and suspendedsolids, comprising adding thereto a water soluble portion of a sludgeproduced in treating petrodissolved or suspended leum oils withcompounds selected from the group consisting of sulfuric anhydride andsulfuric acid, forming aprecipitate 01' water insoluble sulfonate insaid liquid, and removing said 5 precipitate.

18. The process for clarifying aqueous liquids containing substances ofthe class consisting of dissolved coloring matter and suspended solids,which comprises precipitating therein an insoluble sull'onate salt andremoving said precipitate.

JOHN C. BIRD.

